Conventional coal feed systems using gravity flow of solids, such as in a coal feed to coal-fired boilers, tolerate major fluctuations in the coal mass flow rate and suspension density.
Various devices have been built for discharging substances which tend to flow easily by gravity, such as grain. While devices such as those described in U.S. Pat. Nos. 3,289,396, 3,367,724, 4,529,336, 3,424,352, and 4,067,623 are concerned with providing "efficient discharge" of particulate materials from bulk storage tanks and avoiding bridging and incomplete discharging from such tanks, these devices do not maintain a uniform mass flow rate of particulate solids and gas mixture discharged in a uniform manner to a receiving reactor.
The present invention is directed to overcoming this problem in the art both for uniform flow and for reliable continuous flow.
Applicants are not aware of any prior art which, in their judgment as persons skilled in this particular art, would anticipate or render obvious the present invention. However, for the purpose of fully developing the background of the invention, and establishing the state of requisite art, the following art, in addition to Assignee's above-identified related applications, is set forth: U.S. Pat. Nos. 4,482,275; 3,367,724; 4,067,623; 3,424,352; 4,529,336; Re 24,716 (2,794,686); 3,007,744; 2,568,379; 2,400,194; 2,115,023; 3,230,016; 3,285,739; 3,289,396; 4,381,924; 3,479,093; 3,121,593; 3,159,432; 2,499,766; 3,411,832; 3,720,351; 2,806,781; 3,822,919; 699,405; 3,994,702; 4,018,588; 3,001,829; 2,715,551; 2,631,759; Japanese patents 98,030; 102,431; and 107,316; "Monitor Aeration Devices", Monitor Manufacturing Company, Elburn, Ill. 60119.